Field of the Invention
The present disclosure relates generally to valves and more specifically relates to valve cover locks.
Description of the Related Art
Wellbores drilled through subsurface rock formations to extract oil and gas may be treated by pumping various types of fluids and/or other materials into the formations. Fluid pumping treatments can include, for example, hydraulic fracturing, wherein fluid is pumped into the formation at pressures that exceed a fracture pressure of the formations. As another example, drilling mud can be pumped into or out of a wellbore or formation for purposes such as sealing off porous rock layers, equalizing pressures, cooling drilling components and flushing out cuttings, among others. Other fluid treatments may include, for example, pumping acid into the wellbore to dissolve minerals present in the pore spaces of the formation. In conducting fluid pumping treatments on one or more wells, pumping equipment can be used, which can include pumps (e.g., mud pumps, water pumps or other fluid pumps), connections, power sources, fluid ends, power ends, transmissions, motors, conduits and other components of pumping systems. At least some pumping equipment, such as pumps, can include parts or components that degrade over time during use, such as due to friction, temperature, pressure, exposure and the like, which can be referred to as wear components.
Referring now to FIG. 1, a drilling rig 1 for oil and gas operations may be used to drill a wellbore 2 in a reservoir 3 from a surface location 4, which may be or include a ground surface, a drilling platform, or any other location outside of the wellbore 2 from which drilling may be controlled. The drilling rig 1 can include a drill string 5 suspended therefrom, such as a drill string comprised of a continuous length of pipe assembled from a series of relatively short tubing sections, or tubulars 6, connected to one another. The drill string 5 can include one or more of many drilling tools, bottom hole assemblies or other components for hydrocarbon exploration, such as a drill bit 7. In at least some instances, drilling fluids 8 for supporting drilling operations, such as water, mud, lubricants, water-based or oil-based suspensions of clays, chemicals, particulates, coolants, other materials and/or combinations thereof, can be pumped into and/or out of a wellbore 2 during drilling operations, e.g., for purposes such as those mentioned above. For example, drilling fluids 8 can be pumped from location 4 down drill string 5 and back up through an annulus 9 of wellbore 2. However, this need not be the case and other pumping configurations are possible. Accordingly, a drilling rig 1 can include one or more pumps, such as mud pump 10, for pumping drilling fluids.
As shown in FIGS. 2 and 3, a conventional mud pump 10 can include a power end 12 and a fluid end 14. Power end 12 can be adapted to convert rotational movement from a motor or other power source (not shown) applied to one or more drive shafts 16 into linear movement or other movement for operating fluid end 14. Fluid end 14 can include one or more fluid end modules 18 having one or more inlets, or ports 20, and one or more outlets, or outlet ports 22, for routing drilling fluid, such as drilling mud, into and out of fluid end 14. Each module 18 can include one or more valves for drawing fluid through fluid end 14. The valves can be disposed within modules 18 and secured in place with valve cover locks 24 for supporting operation of the valves. More specifically valve cover locks 24 can be coupled to modules 18 for securing valve covers 26 in place during pumping operations. Conventional valve cover locks 24 can include a threaded ring 28 and a threaded valve pot cover 30 for keeping a valve cover 26 in place during pumping operations. However, because mud pumps can operate at relatively high pressures, for example up to 7500 pounds per square inch (PSI), valve cover locks 24 should be able to withstand forces applied to valve cover 26 during pumping. As shown in FIGS. 2 and 3, conventional, threaded valve pot covers 30 typically are large enough in diameter to allow for removal of valve cover 26 upon removal of cover 30 from ring 28. As a result, a relatively large amount of torque can be required to tighten cover 30 adequately to withstand the operating pressure of a mud pump. For example, for a pump expected to operate at approximately 7500 PSI, up to approximately 8000 or 9000 foot-pounds (ft-lbs) of torque can be needed to properly tighten a conventional cover 30 sufficiently to counteract forces applied to valve cover 26 during preloading operations performed prior to general pumping operations. As such, torques of this magnitude may not be feasible with equipment available at a typical well site and, thus, in at least some cases, conventional covers 30 may not be properly tightened prior to pumping operations.
As a result, the valve cover 26 can be subject to movement over time, or covers 30 can back out over time, for example due to vibrations or other forces experienced during pumping, which can result in reduced performance of the pump. For example, a pump may not be able to operate at its intended working pressure or wear parts may wear more quickly due to improper functioning of the valve resulting from improper placement or movement of valve cover 26. Regardless of whether conventional valve cover locks 24 are properly or otherwise adequately tightened, the valve pot covers 30 may be removed from time to time to service the pump, such as, for example, for servicing or replacing wear parts such as poppet 32, valve guide 34, or other pump components, such as gaskets, fasteners, springs and the like. Of course, the more time that may be needed to remove or replace a valve cover lock during servicing, the greater the down time may be for the pump.
Accordingly, a need exists in the art for a valve cover lock that can be more easily coupled or uncoupled from a pump or fluid end, such as by requiring relatively less torque for proper installation as compared to conventional locks of similar specifications, or by reducing an amount of time that may be needed to service a pump in a manner that may call for removal of one or more valve cover locks. The disclosures and teachings herein are directed to systems and methods for improved valve cover lock structures.